Alarm units generally employ a microcontroller with an optocoupler (micro/opto design) to provide various features of the alarm units. Alarm units based on the micro/opto design have been proven to be reliable while providing excellent performance. Examples of such alarm units are disclosed in U.S. Pat. Nos. 6,369,696 and 6,311,021, which are assigned to the present assignee and are herein incorporated by reference.
However, in attempting to further improve alarm units based on the micro/opto design, it has been found that the micro/opto design has certain constraints. These constraints affect performance and the overall cost of the alarm unit.
Therefore, a need exists in the art for an alarm unit that is not based on the micro/opto design, thereby removing constraints that affect performance and the overall cost of the alarm unit that are attributable to the micro/opto design.